A comprehensive insight on H-type aggregation in Congo red-surfactant systems revealed through spectroscopic and electrochemical study unified with a simulation framework

2019 ◽  
Vol 21 (28) ◽  
pp. 15584-15594 ◽  
Author(s):  
Vinod Kumar ◽  
Dhruvi Patel ◽  
Haridas Pal ◽  
Ketan Kuperkar

Schematic illustration depicting the aggregation phenomenon and shifts in the cationic surfactants-Congo red (CR) dye system investigated through spectral, scattering, voltammetry techniques along with the computational simulation approach.

2019 ◽  
Author(s):  
Noam Benelli ◽  
Roi Gurka ◽  
Yiftach Golov ◽  
Ally Harari ◽  
Gregory Zilman ◽  
...  

AbstractOlfactory navigation in insects, for instance when males search for mates, is a navigational problem of a self-propelled agent with limited sensor capabilities in a scalar field (odor) convected and diffused by turbulent wind. There are numerous navigation strategies proposed to explain the navigation paths of insects to food (flowers) or mating partners (females). In a search for a mate, the males use airborne pheromone puffs in turbulent environments around trees and vegetation. It is difficult to compare the various strategies because of a lack of a single simulation framework that can change a single parameter in time and test all the strategies against a controlled environment. This work aims at closing this gap, suggesting an open source, freely accessible simulation framework, abbreviated MothPy. We implement the simulation framework using another open source package (“pompy”) that recreates a state-of-the-art puff-based odor plume model of Farrell et al. [1]. We add four different navigation strategies to the simulation framework based on and extending the previously published models [2, 3], and compare their performance with different wind and odor spread parameters. We test a sensitivity analysis of the navigation strategies to the plume meandering and to increased turbulence levels that are effectively expressed as the elevated puff spread rates. The simulations are compared statistically and provide an interesting view on the robustness and effectiveness of various strategies. This benchmarking-ready simulation framework could be useful for the biology-oriented, as well as engineering-oriented studies, assisting to deduce the evolutionary efficient strategies and improving self-propelled autonomous systems in complex environments.


Author(s):  
Martijn IJtsma ◽  
Lanssie M. Ma ◽  
Karen M. Feigh ◽  
Amy R. Pritchett

This document describes a demonstration of the computational simulation framework Work Models that Compute (WMC). WMC is a framework for the objective evaluation of function allocation between humans and robots. The WMC framework has been used to study the impact of function allocation on both the air traffic management and spacecraft operations work domains. Recent advances include modeling of human-robot control modes, locomotion, failures and physical resources. We propose a demonstration of WMC showcasing how WMC can provide useful, objective and quantitative insight in the trade-offs asso-ciated with function allocation. In the demonstration, we will analyze function allocation for an on-orbit maintenance scenario. We will first show how minor changes to a function allocations can have major ef-fects on the emergent work patterns that result from the simulation framework. Second, we will demon-strate an analysis of 10-15 possible function allocations (defined in advance) and cross-compare their char-acteristics based on measures such as the idle time, taskload for each agent, information transfer require-ments, physical resources exchanges and others. This will show the framework’s capability to rapidly ex-plore the function allocation trade-space and allow the designer to make more informed trade-offs.


Author(s):  
Tung Xuan Vuong ◽  
Willow Yangliu Li ◽  
Ahmed Al-Jumaily ◽  
Neel Pandey

Abstract The paper presents an investigation into the noise generated by structural vibration of an electric motor used in appliance products using Computational Simulation Approach. In particular, a 3-D numerical simulation model is specifically developed to predict the frequency response of the stator under three different simulation conditions: radial force only, tangential force only and the combination of both forces. The obtained data is used to analyze the acoustic generation in the far-field. Experimental is used to validate the predicted results. It shows the predicted results are very close to experimental results.


Chemosphere ◽  
2021 ◽  
Vol 262 ◽  
pp. 127680
Author(s):  
Mohammad Abbasi ◽  
Javad Aminian-Dehkordi ◽  
Seyyed Mohammad Mousavi

2017 ◽  
Vol 41 (17) ◽  
pp. 9142-9151 ◽  
Author(s):  
Nilesh Dharaiya ◽  
Urja Patel ◽  
Debes Ray ◽  
Vinod K. Aswal ◽  
Nandhibatla V. Sastry ◽  
...  

The unusual effect of pH on the aggregate morphology of pH dependent surfactant systems.


1993 ◽  
Vol 42 (5) ◽  
pp. 762
Author(s):  
ZHANG SHI-CHANG ◽  
WANG WEN-YAO ◽  
XU YONG

Lubricants ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Michael Pusterhofer ◽  
Florian Summer ◽  
Michael Maier ◽  
Florian Grün

Optimizing the surface topography of cast iron crankshafts offers the opportunity to use this material as an alternative to steel in high-performance combustion engines. In the past, this was not possible due to the higher wear on bearing shells and the higher friction losses in relation to forged steel shafts. In order to find an optimized shaft micro topography, the friction and wear behavior of steel and cast iron shafts with different surface treatments were compared to each other, using a combined physical (experimental) and a virtual (computational) simulation approach. The experiments were carried out with a rotary tribometer using a journal bearing test configuration with the possibility to test real-life bearing shells and shaft specimens, manufactured from real-life crankshafts. In the experiments, a polished steel shaft with low bearing wear was effective. The optimization of cast iron crankshafts by a novel surface treatment showed a significant reduction of bearing wear in relation to the classical surface finishing procedures of cast iron shafts. A computational simulation approach, considering the real-life micro topography by using the Navier–Stokes equations for the calculation of micro hydrodynamics, supports the assessment of fluid friction. The virtual simulation shows, in accordance to the experimental results, only a minor influence of the investigated shaft topographies on the fluid friction. Further optimization of shaft surfaces for journal bearing systems seems possible only by the usage of patterned micro topographies.


Aging Cell ◽  
2017 ◽  
Vol 16 (6) ◽  
pp. 1244-1255 ◽  
Author(s):  
Timothy E. Hoffman ◽  
Katherine J. Barnett ◽  
Lyle Wallis ◽  
William H. Hanneman

Author(s):  
M. W. Woo ◽  
S. Afshar ◽  
H. Jubaer ◽  
B. Chen ◽  
J. Xiao ◽  
...  

Self-sustained fluctuating airflow behaviour in spray drying chambers is in essence an unsteady phenomenon requiring the transient CFD simulation framework. There is currently, however, a mixture of steady state and transient CFD simulations of spray dryers practised and reported in the literature. The choice between steady state and transient approach significantly affects the computation time of the simulation and subsequently the adoption of this approach by industry. This paper firstly examines in detail the bottleneck in computation time of the transient simulation approach. Based on past reports, this review paper then presents a discussion and provides several recommendations on the use of steady state and transient simulation approach for spray dryers. Keywords: CFD simulation, spray drying, transient, steady state, fluctuation 


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